Answer:
Rate in still water = 45 km/h
Rate of the current = 10 km/h.
Step-by-step explanation:
Let the rate of the current be x and rate in still water be y.
So the rate of the boat upstream is y - x and the rate downstream = x + y.
Rate upstream = distance / time
y - x = 105/3 = 35 ...... (1)
Rate downstream:
y + x = 165/3 = 55 .......(2)
Adding (1) + (2):
2y = 90
y = 45 km/h.
Using equation (1):
45 - x = 35
x = 45-35 = 10 km/h.
We're going to use the equation given but let's first make sure we understand what the equation IS saying:
Area of a kite= [(1st diagonal) × (2nd diagonal)]/2
Now, let's find the 2 diagonals. In the case of kite shapes one of the diagonals is the line that goes from W to Y and the other is the line going from X to Z. In a kite they will always cross (no matter their lengths).
Now that we know the diagonals we can add the lengths that are given for each line to know what to multiply.
Line W to Y: 20+12= 32
Line X to Z: 12+12= 24
Now let's plug these numbers into the equation (it doesn't matter the order of the diagonals because we're just gonna be multiplying them either way!)
So...
(32×24)/2= 384 units squared (because it is area)
4 / 5 - 2 / 3 ( taking LCM on bottom )
= ( 12 - 10 ) / 15
= 2 / 15 Ans
